A currency pair is the quotation of the relative value of a currency unit against the unit of another currency in the foreign exchange market.
The first currency, the one denoted on the left side of the pair, is called Base Currency and is in essence our product i.e. the one we wish to sell or buy.
The second currency, the one denoted on the right of the pairs is called Quote or Counter Currency.
The rules for formulating standard currency pair notations result from accepted priorities attributed to each currency.
The most popular currency pairs are:
EUR/USD, GBP/USD, USD/JPY, USD/CHF, NZD/USD, AUD/USD, USD/CAD and AUD/CAD